1. Field of the Invention
The present invention relates to a method for producing a solid-state imaging device, a solid-state imaging device, and a camera, for example, a method for producing a solid-state imaging device such as a charge coupled device (CCD), the solid-state imaging device, and a camera provided with the solid-state imaging device.
2. Description of the Related Art
A method for producing a solid-state imaging device in related art will be described with reference to FIGS. 1A and 1B, FIGS. 2A and 2B, and FIGS. 3A and 3B.
As shown in FIG. 1A, an n-type signal charge storage region 113, an n-type transfer channel region 115, and a channel stop region 118 are formed in a p-type well 112 of an n-type silicon substrate (substrate) 111. The p-type well 112 between the signal charge storage region 113 and the transfer channel region 115 functions as a read out gate region 117. A gate insulation film 120 is formed on the substrate 111, a transfer electrode 121 is formed on the gate insulation film 120, and an insulation film 122 is formed to cover the transfer electrode 121. The transfer electrode 121 and the insulation film 122 are used as a mask and applied with ion implantation method to thereby form a p-type hole storage region 114. A light receiving unit 105 has the signal charge storage region 113 and the hole storage region 114. And a vertical transfer unit 107 has the transfer channel region 115 and the transfer electrode 121. A read out gate unit 106 has the read out gate region 117 and the transfer electrode 121.
As shown in FIG. 1B, a shield film 123 is formed to cover the transfer electrode 121. As the shield film 123, a high shieldability metal film such as aluminum or tungsten is formed by spattering method or chemical vapor deposition (CVD) method.
As shown in FIG. 2A, a resist film 126 with a mask aperture C at a region of the light receiving unit 105 is formed by coating a resist film on the shield film 123, exposing and developing the same.
As shown in FIG. 2B, the resist film 126 is used as a mask and a portion of the shield film 123 exposed from the mask aperture C is removed to form an aperture portion 123a in the shield film 123. As shown in FIG. 3A, the resist film 126 is removed.
As shown in FIG. 3B, a protective insulation film 125 is formed on the substrate 111 to cover the shield film 123. The protective film 125 is made from silicon oxide film or silicon nitride film, for example.
As the following steps, if necessary, a color filter and an on-chip lens are formed to thereby produce the solid-state imaging device.
Japanese Unexamined Patent Publication No. 7-202160 and No. 8-32045 disclose such aperture portion 123a for exposing a region to be the light receiving unit 105 by applying a patterning process used with the resist film 126, for example.